Dressing assemblies for wound treatment using reduced pressure

ABSTRACT

A dressing assembly for use with a reduced pressure treatment system, the dressing assembly develops a directed force under reduced pressure. The directed force may be a radial force or a closing force. The dressing assembly includes a shaped dressing bolster having a shaped extremity that is operable to evenly deliver the radial force and to distribute reduced pressure. Numerous shapes may be used for the shaped extremity. The dressing assembly may further include an over-drape to assist in creating a seal over the shaped dressing bolster and against a portion of a patient&#39;s epidermis.

RELATED APPLICATIONS

The present invention claims the benefit, under 35 USC §119(e), of thefiling of U.S. Provisional Patent Application Ser. No. 61/057,807,entitled “Reduced-pressure Surgical Wound Treatment System,” filed May30, 2008; U.S. Provisional Patent Application Ser. No. 61/057,798,entitled “Dressing Assembly For Subcutaneous Wound treatment UsingReduce Pressure,” filed May 30, 2008; U.S. Provisional PatentApplication Ser. No. 61/057,808, entitled “See-Through, Reduced-PressureDressing,” filed May 30, 2008; U.S. Provisional Patent Application Ser.No. 61/057,802, entitled “Reduced-Pressure Dressing Assembly For Use inApplying a Closing Force,” filed May 30, 2008; U.S. Provisional PatentApplication Ser. No. 61/057,803, entitled “Reduced-Pressure,Linear-Wound Treatment System,” filed May 30, 2008; U.S. ProvisionalPatent Application Ser. No. 61/057,800, entitled “Reduced-Pressure,Compression System and Apparatus for use on a Curved Body Part,” filed,May 30, 2008; U.S. Provisional Patent Application Ser. No. 61/057,797,entitled “Reduced-Pressure, Compression System and Apparatus for use onBreast Tissue,” filed May 30, 2008; U.S. Provisional Patent ApplicationSer, No. 61/057,805, entitled “Super-Absorbent, Reduced-Pressure WoundDressing and System,” filed May 30, 2008; U.S. Provisional PatentApplication Ser. No. 61/057,810, entitled “Reduced-Pressure, CompressionSystem and Apparatus for use on a Joint,” filed May 30, 2008; U.S.Provisional Patent Application Ser. No. 61/121,362, entitled“Reduced-Pressure Wound treatment System Employing an AnisotropicDrape,” filed Dec. 10, 2008; and U.S. Provisional Patent ApplicationSer. No. 61/144,067, entitled “Reduced-Pressure, Compression System andApparatus for use on a Joint,” filed Jan. 12, 2009. All of theseprovisional applications are incorporated herein by reference for allpurposes.

BACKGROUND

The present invention relates generally to medical treatment systems,and more particularly, to reduced-pressure wound treatment systemssuitable for use with surgical wounds and other tissue sites.

Physicians perform millions of surgical procedures each year around theworld. Many of the procedures are performed as open surgery and anincreasing number are performed using minimally invasive surgery, suchas endoscopic, arthroscopic, and laparoscopic procedures. As oneexample, the American Society for Aesthetic Plastic Surgery reports thatthere were more than 450,000 liposuction procedures in the United Statesin 2007.

Surgical procedures involve acute wounds, e.g., an incision, in the skinand related tissue. In many instances, the incision is closed at theconclusion of the procedure using a mechanical apparatus, such asstaples or suture, or closed using adhesives. Thereafter, the wound isoften merely covered with a dry, sterile bandage. Of course, there isusually more disruption than just at the epidermis.

With many surgical procedures, particularly those done with minimallyinvasive techniques, much of the disruption or damage is below theepidermis, or at a subcutaneous level. Again, as one example, in onetype of liposuction procedure, after the introduction of a tumescentfluid (saline, mild painkiller, and epinephrine), the surgeon will use atrocar and cannula with suction to remove fatty areas. In doing so, itis not uncommon to have subcutaneous voids and other tissue defectsformed at tissue sites remote from the incision through which thecannula was placed or other incisions through which equipment wasplaced. The damaged tissue will need time and care to heal and poses anumber of potential complications and risks including edema, seroma,hematoma, further bruising, and ecchymosis to name some.

To facilitate healing after many surgical procedures, such asliposuction, depending on the body part involved, a firm-fitting wrap orelastic compression garment may be used for weeks on the patient. Thesedevices are at times uncomfortable, may apply compression in anon-uniform manner, and can be difficult to take off and put on. Inaddition, because of edema, a number of different compression garmentsmay be required for a single patient. It would be desirable to addresssome or all of the shortcomings of post-surgical wound care at theincision and at the undermined subcutaneous tissue.

BRIEF SUMMARY

Shortcomings with aspects of wound care are addressed by theillustrative embodiments herein. According to one illustrativeembodiment, a dressing assembly for use with a reduced pressuretreatment system includes a shaped dressing bolster, which has a firstsurface, a second (inward-facing) surface, and an extremity. The shapeddressing bolster is formed from a medical bolster material. Theextremity has an oblique surface. The shaped dressing bolster isoperable to evenly distribute a compressive force.

According to another illustrative embodiment, a dressing assembly foruse with a reduced-pressure treatment system includes a shaped dressingbolster, which has a first surface, a second (inward-facing) surface,and an extremity. The shaped dressing bolster is formed from a medicalbolster material operable to distribute reduced pressure. The dressingassembly further includes an over-drape that is coupled to the firstsurface of the shaped dressing bolster and the extremity of the shapeddressing bolster. The shaped dressing bolster is operable to evenlydistribute a compressive force that results when the shaped dressingbolster is subjected to reduced pressure.

According to another illustrative embodiment, a dressing assembly foruse with a reduced pressure treatment system includes a shaped dressingbolster, which has a shaped extremity, a first surface, and a second(inward-facing) surface. The dressing assembly further includes anover-drape disposed over the first surface of the shaped dressingbolster and that is coupled to a least a portion of the first surface ofthe shaped dressing bolster. The over-drape may extend beyond the shapeddressing bolster to form a drape extension, which has a first side and asecond, inward-facing side. An adhesive perimeter strip may be coupledto the second side of the drape extension to provide a seal between apatient and the over-drape.

According to another illustrative embodiment, a dressing assembly foruse with a reduced-pressure treatment system includes a shaped dressingbolster, which has a shaped extremity, a first surface, and a second(inward-facing) surface. The shaped dressing bolster is operable toevenly distribute a compressive force. The dressing assembly furtherincludes an over-drape disposed over the first surface of the shapeddressing bolster that extends over the shaped dressing bolster beyondthe shaped dressing bolster to form a drape extension. The drapeextension has a first surface and a inward-facing, second surface. Thedressing assembly further includes an inner layer, which has a firstsurface and a second, inward-facing surface. The first surface of theinner layer is coupled, at least in part, to a portion of the secondsurface of the shaped dressing bolster. The inner layer is formed with atreatment area aperture. The shaped dressing bolster is formed from amedical bolster material operable to distribute a reduced pressure.

According to another illustrative embodiment, a method of manufacturinga shaped dressing bolster for use with a reduced pressure treatmentsystem includes the steps of: providing medical bolster material andforming a shaped dressing bolster from the medical bolster material. Theshaped dressing bolster is operable to distribute reduced pressure andto evenly distribute a compressive force, and the shaped dressingbolster is formed with a shaped extremity.

Other features and advantages of the illustrative embodiments willbecome apparent with reference to the drawings and the detaileddescription that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be obtainedby reference to the following Detailed Description when taken inconjunction with the accompanying Drawings wherein:

FIG. 1 is a schematic, perspective view of an illustrative embodiment ofa reduced-pressure surgical wound treatment system shown over anincision and above damaged subcutaneous tissue;

FIG. 2 is a schematic, cross-section of a portion of an illustrativeembodiment of a reduced-pressure surgical wound treatment system shownon intact skin and over an area of damaged subcutaneous tissue;

FIG. 3 is a schematic, cross-section of a portion of an illustrativeembodiment of a reduced-pressure surgical wound treatment system showndeployed on a torso of a patient;

FIG. 4 is a schematic, cross-section of a portion of an illustrativeembodiment of a reduced-pressure surgical wound treatment system showndeployed on a torso of a patient;

FIG. 5 is a schematic, perspective view of an illustrative embodiment ofa dressing assembly;

FIG. 6 is a schematic, cross-section of the illustrative embodiment ofthe dressing assembly of FIG. 5;

FIG. 7 is a schematic, cross-section of an illustrative embodiment ofanother dressing assembly;

FIG. 8 is a schematic, cross-section of an illustrative embodiment ofanother dressing assembly;

FIG. 9 is a schematic, perspective view of a portion of an illustrativeembodiment of a dressing assembly;

FIG. 10 is a schematic, cross-section of an illustrative embodiment of adressing assembly;

FIG. 11 is a schematic, cross-section of an illustrative embodiment of adressing assembly;

FIG. 12 is an exploded, schematic, perspective view of an illustrativeembodiment of a dressing assembly;

FIG. 13 is a schematic, cross-section of an illustrative embodiment of adressing assembly;

FIG. 14 is an exploded, schematic, perspective view of an illustrativeembodiment of a dressing assembly;

FIG. 15 is a schematic, perspective view of an illustrative embodimentof a dressing assembly;

FIG. 16 is a cross sectional view of a portion of the dressing assemblyof FIG. 15; and

FIG. 17 is an exploded, schematic, perspective view of an illustrativeembodiment of a dressing assembly.

DETAILED DESCRIPTION

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown, by way of illustration, specific embodiments inwhich the invention may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice theinvention, and it is understood that other embodiments may be utilizedand that logical structural, mechanical, electrical, and chemicalchanges may be made without departing from the spirit or scope of theinvention. To avoid detail not necessary to enable those skilled in theart to practice the invention, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is, therefore, not to be taken in a limiting sense, and thescope of the present invention is defined only by the appended claims.

Referring now to FIG. 1, a reduced-pressure system 10 for treatingtissue, such as subcutaneous tissue in a peri-incisional region or anincision, according to one illustrative embodiment is shown. As usedherein, “or” does not require mutual exclusivity. The reduced-pressuresystem 10 is shown in a peri-incisional region around an incision 12,which is through epidermis 14, or skin, and dermis 16 and reaching intoa hypodermis, or subcutaneous tissue 18. The subcutaneous tissue 18 mayinclude numerous tissue types, such as fatty tissue or muscle. Adamaged, or undermined or abnormal, subcutaneous tissue site 20 is shownextending from the incision 12 and includes, in this instance, asubcutaneous defect, dead space, or void 22.

The damaged subcutaneous tissue 20 may have been caused by a surgicalprocedure, such as liposuction. The damaged subcutaneous tissue 20 mayinclude voids, such as the void 22, open spaces, or various defects thatcan be troublesome for a number of reasons such as allowing fluids tobuild that may result in edema. The term “fluid” as used hereingenerally refers to gas or liquid, but may also include any otherflowable material, including but not limited to gels, colloids, andfoams.

The system 100 may help the damaged subcutaneous tissue 20 to beapproximated—brought together or near-to improve healing whileminimizing or eliminating skin irritation. The system 100 may alsodevelop a closing force directed toward the incision 12 and that mayhelp hold the incision closed or provide support. The system 100 mayhelp minimize shear stress on deep wounds, e.g., void 22. The system 100may also help the incision 12 remain dry, help avoid dead spaceformation, improve perfusion, and avoid seroma and hematoma formation.In addition, system 100 may help minimize bruising and edema secondaryto certain surgical procedures. The system 100 may provide comfort forthe patient and a relatively shortened duration that the system 100 maybe required on the patient. With the system 100, dressing changes may beeliminated or the number of required changes minimized.

The incision 12 may be closed using any mechanical closing means such asstaples or sutures, or may be closed using an adhesive, but is shown inthis illustrative embodiment as being closed with suture 13. Thereduced-pressure system 10 typically is for treating an area and, inparticular, is typically for treating a subcutaneous tissue site 20 andthe tissue around subcutaneous tissue 20, but the reduced-pressuresystem 10 may also be used to treat a more limited area around theincision 12.

The reduced-pressure system 10 includes a dressing assembly 30, whichincludes a shaped dressing bolster 32, a sealing subsystem 60, and areduced-pressure subsystem 80. The reduced-pressure system 10 develops aforce, which may include a vertical force or a closing force. As used inthis context and herein, “vertical” means parallel to arrows 24irrespective of orientation but shown vertically in FIG. 1. Thedeveloped force in the vertical may be a compressive force or a liftingforce. In the illustrative embodiment, the net vertical force ispresented as a compressive force represented by the arrow 24, and theclosing force is shown by arrows 26. The compressive force 24 mayrealized at the subcutaneous tissue 20 or deeper, including at an organ.As used herein subcutaneous tissue may include the deeper tissues aswell. The compressive force 24 may be directed vertically (i.e.,generally toward a center line of patient's body or a body portion orwith reference to the shaped dressing bolster 32 from the first side 34to the second side 34. The compressive force 24 may reach subcutaneoustissues. The magnitude of the vertical force 24 may be influenced by thesize and shape of the shaped dressing bolster 32.

In some situations, it may be desirable to have the shaped dressingbolster 32 deliver the vertical force as a lifting force. The densityand thickness of the shaped dressing bolster 32 are variables forcontrolling lifting. For example, if the density of a medical bolstermaterial is less than the density of the tissue, e.g., epidermis, at thetissue site, a lifting force may be generated. As a substantially thickportion of a shaped dressing bolster 32 experiences reduced pressure,the shaped dressing bolster contracts toward a central portion from alldirections. The portion of the shaped dressing bolster 32 near thepatient's epidermis will pull away from the patient's epidermis sincethe central portion is above the patient's epidermis. This creates avertical lifting force. A portion of the shaped dressing bolster mayprovide a compressive force, while another portion—generally a centralportion—provides a lifting force with respect to the patient or thesystem.

The illustrative embodiment of FIG. 1 is presented with the verticalforce applying a compressive force 24. As described further below, theshaped dressing bolster 32 may be shaped and configured to allow thecompressive force to be distributed fairly evenly over the patient'sepidermis 14 and beneath the epidermis 14. Otherwise, if there are areasof substantially increased force as compared to other areas, skinirritation may result. The reduced-pressure system 10 may also beoperable to develop the closing force, i.e. a substantially tangentialforce towards an interior portion of the dressing assembly 30,represented by the reference numerals 26. The closing force 26 remainssubstantially within the plane of the epidermis 14; in other words, theclosing force 26 operates mainly within the epidermis 14. In addition,the reduced-pressure system 10 is operable to deliver reduced pressureto the incision 12 that, depending on the incision and the state ofhealing, may be realized at the level of the subcutaneous void 22 tohelp approximate—bring together—the tissues in that region as well as tohelp remove any air or any other fluids or provide reduced-pressuretherapy. The compressive force 24 may also close or help close the void22.

As used herein, “reduced pressure” generally refers to a pressure lessthan the ambient pressure at a tissue site that is being subjected totreatment. In most cases, this reduced pressure will be less than theatmospheric pressure at which the patient is located. Alternatively, thereduced pressure may be less than a hydrostatic pressure at the tissuesite. Unless otherwise indicated, values of pressure stated herein aregauge pressures. The reduced pressure delivered may be constant orvaried (patterned or random) and may be delivered continuously orintermittently. Although the terms “vacuum” and “negative pressure” maybe used to describe the pressure applied to the tissue site, the actualpressure applied to the tissue site may be more than the pressurenormally associated with a complete vacuum. Consistent with the useherein, an increase in reduced pressure or vacuum pressure typicallyrefers to a relative reduction in absolute pressure.

The dressing assembly 30 includes the shaped dressing bolster 32 thathas a first side 34 and a second, inward (skin-facing or patient-facing)side 36. The shaped dressing bolster 32 may be sized and shaped tosubstantially match the estimated area of damaged subcutaneous tissue 20although a larger or smaller size may be used in different applications.The shaped dressing bolster 32 has a peripheral edge 38. The shapeddressing bolster 32 may be made of a number of different medical bolstermaterials, i.e., materials suitable for use in medical applications andthat may be made sterile. In one illustrative embodiment, the shapeddressing bolster 32 is made from a medical bolster material that is amanifold material. The term “manifold” as used herein generally refersto a substance or structure that is provided to assist in applyingreduced pressure to, delivering fluids to, or removing fluids from atissue site. The manifold material typically includes a plurality offlow channels or pathways that distribute fluids provided to and removedfrom the tissue site around the manifold material. The flow channels orpathways may be interconnected. The manifold material may be abiocompatible material that is capable of being placed in contact withtissue site and distributing reduced pressure to the tissue site.Examples of manifold materials may include, for example, withoutlimitation, materials that have structural elements arranged to formflow channels, such as, for example, cellular foam, open-cell foam,porous tissue collections, liquids, gels, and foams that include, orcure to include, flow channels.

The manifold material, or medical bolster material, may be porous andmay be made from foam, gauze, felted mat, or any other material suitedto a particular biological application. In one embodiment, the manifoldmaterial is a porous foam and includes a plurality of interconnectedcells or pores that act as flow channels. The porous foam may be apolyurethane, open-cell, reticulated foam such as GranuFoam® materialmanufactured by Kinetic Concepts, Incorporated of San Antonio, Tex.Other embodiments may include “closed cells.”

The reticulated pores of the Granufoam® material, that are typically inthe range of about 400 to 600 microns, are helpful in carrying out themanifold function, but other materials may be used. The density of themedical bolster material, e.g., Granufoam® material, is typically in therange of about 1.3-1.6 lb/ft³ (20.8 kg/m³-25.6 kg/m³). A material with ahigher density (smaller pore size) than Granufoam® material may bedesirable in some situations. For example, the Granufoam® material orsimilar material with a density greater than 1.6 lb/ft³ (25.6 kg/m³) maybe used. As another example, the Granufoam® material or similar materialwith a density greater than 2.0 lb/ft³ (32 kg/m³) or 5.0 lb/ft³ (80.1kg/m³) or even more may be used. The more dense the material is, thehigher compressive force that may be generated for a given reducedpressure. If a foam with a density less than the tissue at the tissuesite is used as the medical bolster material, a lifting force may bedeveloped.

The medical bolster material may be a reticulated foam that is laterfelted to thickness of about ⅓ the foam's original thickness. Among themany possible materials, the following materials may be used: Granufoam®material or a Foamex® technical foam (www.foamex.com). In some instancesit may be desirable to add ionic silver to the foam in a microbondingprocess or to add other substances to the medical bolster material suchas antimicrobial agents. The medical bolster material may be isotropicor anisotropic depending on the exact orientation of the forces desiredduring reduced pressure. The medical bolster material could be abio-absorbable material. A comfort layer of material may be added aswell between the medical bolster material and the patient.

The sealing subsystem 60 includes an over-drape 62, or drape or sealingmember. The over-drape 62 may be an elastomeric material or may be anymaterial that provides a fluid seal. “Fluid seal,” or “seal,” means aseal adequate to hold reduced pressure at a desired site given theparticular reduced-pressure subsystem involved. The over-drape 62 may,for example, be an impermeable or semi-permeable, elastomeric material.“Elastomeric” means having the properties of an elastomer. Elastomericmaterial is generally a polymeric material that has rubber-likeproperties. More specifically, most elastomers have elongation ratesgreater than 100% and a significant amount of resilience. The resilienceof a material refers to the material's ability to recover from anelastic deformation. Examples of elastomers may include, but are notlimited to, natural rubbers, polyisoprene, styrene butadiene rubber,chloroprene rubber, polybutadiene, nitrile rubber, butyl rubber,ethylene propylene rubber, ethylene propylene diene monomer,chlorosulfonated polyethylene, polysulfide rubber, polyurethane, EVAfilm, co-polyester, and silicones. Specific examples of over-drapematerials include a silicone drape, 3M Tegaderm® drape, acrylic drapesuch as one available from Avery Dennison, or an incise drape.

The over-drape 62 may be coupled to the shaped dressing bolster 32. Ifcoupling is desired, the coupling may occur in many ways. The over-drape62 and shaped dressing bolster 32 may be coupled using adhesives, suchas an acrylic adhesive, silicone adhesive, hydrogel, hydrocolloid, etc.The over-drape 62 and shaped dressing bolster 32 may be bonded by usingany technique, including without limitation welding (e.g., ultrasonic orRF welding), bonding, adhesives, cements, etc. The over-drape 62 andshaped dressing bolster 32 may be coupled partially, completely, or notat all. Structure may be added to the bond to make the over-drape 62behave anisotropically in a desired direction, i.e. to make ananisotropic drape material. The anisotropic drape material is configuredto move, contract, or expand in a given direction or axis to a greaterextent compared to another direction or axis. This behavior is alsodiscussed in connection with FIG. 9 below. As used herein, the term“coupled” includes coupling via a separate object and includes directcoupling. The term “coupled” also includes two or more components thatare continuous with one another by virtue of each of the componentsbeing formed from the same piece of material. Also, the term “coupled”may include chemical, such as via a chemical bond, mechanical, thermal,or electrical coupling. Fluid coupling means that fluid is incommunication between the designated parts or locations.

In the illustrative embodiment of FIG. 1, the over-drape 62 may be sizedto extend beyond the shaped dressing bolster 32 to form a drapeextension 64. The drape extension 64 has a first surface 66 and asecond, tissue-facing surface 68. The over-drape 62 may be sealedagainst the epidermis 14 of the patient (or against another layer, suchas a gasket or an additional sealing member) using a sealing apparatus69 for providing a fluid seal. As used herein, reference to a seal onthe patient's epidermis should be deemed to include sealing againstanother layer, such as a film gasket, which can contact and seal withthe patient's epidermis. The fluid seal allows a reduced pressure to bemaintained by the reduced-pressure subsystem 80. The sealing apparatus69 may take numerous forms, such as an adhesive 70; a sealing tape, ordrape tape or strip; double-side drape tape; paste; hydrocolloid;hydrogel; or other sealing means. If a tape is used, it may be formed ofthe same material as the over-drape 62 with a pre-applied,pressure-sensitive adhesive. The adhesive 70 may be applied on thesecond surface 68 of drape extension 64. The adhesive 70 provides asubstantially fluid seal between the over-drape 62 and the epidermis 14of the patient. Before the over-drape 62 is secured to the patient,adhesive 70 may have removable strips, or releasable backing, coveringthe adhesive 70. The over-drape 62 may be formed as an integral drape orformed by coupled segments or portions.

The reduced-pressure subsystem 80 includes a reduced-pressure source 82,or therapy unit. The reduced-pressure source 82 may be a vacuum pump,wall suction, or other source. The reduced-pressure source 82 providesreduced pressure as a part of the system 10. While the amount and natureof reduced pressure applied to a tissue site will typically varyaccording to the application, the reduced pressure will typically bebetween −5 mm Hg and −500 mm Hg and more typically between −100 mm Hgand −300 mm Hg.

In order to maximize patient mobility and ease, the reduced-pressuresource 82 may be a battery-powered, single-use reduced-pressuregenerator. The battery-powered, single-use reduced-pressure generatorfacilitates application in the operating room and provides mobility andconvenience for the patient during the rehabilitation phase. For manyprocedures, it is believed that the patient would be directed to wearthe reduced-pressure system 10 for three to five days and may bedirected to wear the reduced-pressure system 10 for 15 days or more.Still, this treatment time can be a time period less than conventionaltreatments, such as conventional compressive garments, which are oftenworn for up to six weeks. Accordingly, the battery life or powerprovisions for such a reduced-pressure source 82 may need to accommodateup to 15 days of operation. Other sources of reduced pressure may beutilized, such as V.A.C.® therapy unit, which is available from KCl ofSan Antonio, Tex., or a wall suction unit. The reduced-pressure source82 could also be supplied by a portable mechanical device, such as apiston in a tube, depending on how much leakage there is with the fluidseal between the shaped dressing bolster 32 and the epidermis 14.

In the illustrative embodiment of FIG. 1, the reduced-pressure source 82is shown having a battery compartment 84 and a canister region 86 withwindows 88 that allow a visual indication of the level of fluid withincanister 86. An interposed membrane filter, such as hydrophobic oroleophobic filter, may be interspersed between a reduced-pressuredelivery conduit, or tubing, 90 and the reduced-pressure source 82.

The reduced pressure developed by reduced-pressure source 82 isdelivered through the reduced-pressure delivery conduit 90 to areduced-pressure interface 92, which may be an elbow port 94. In oneillustrative embodiment, the elbow port 94 is a TRAC® technology portavailable from KCl of San Antonio, Tex. The reduced-pressure interface92 allows the reduced pressure to be delivered through the sealingsubsystem 60 and realized within an interior portion of sealingsubsystem 60. In this illustrative embodiment, the port 94 extendsthrough the over-drape 62 and into shaped dressing bolster 32.

In operation, the reduced-pressure system 10 may be applied in theoperating room after a surgical procedure on the patient or appliedelsewhere. The second surface 36 of the shaped dressing bolster 32,which may include a comfort layer (see, e.g., FIG. 16) would be placedagainst the patient's epidermis 14 with the shaped dressing bolster 32placed over the damaged subcutaneous tissue site 20 and with a portionover the incision 12. The dressing assembly 30 may be pre-sized for thetypical application involved in the procedure performed by a healthcareprovider or sized at the time. The dressing assembly 30 may be sized,shaped, and configured to work in different anatomical applications suchas abdominal, chest, thighs, extremities, etc.

If the over-drape 62 has not already been coupled (see otherillustrative embodiments) to the shaped dressing bolster 32, theover-drape 62 would then be placed over the first surface 34 of theshaped dressing bolster 32 with an extra portion extending beyond theperipheral edge 38 to form the drape extensions 64. The drape extensions64 may then be taped down (see 172 in FIG. 2) or an adhesive 70 (FIG. 1)used to form a fluid seal between the over-drape 62 and the patient'sepidermis 14. The fluid seal need only be adequate to allow thereduced-pressure system 10 to hold a reduced pressure at a desiredlocation. The reduced-pressure interface 92 would then be applied if notalready installed, and the reduced-pressure delivery conduit 90 would becoupled at one end. The other end of the reduced-pressure deliveryconduit 90 would then be coupled to the reduced-pressure source 82. Thereduced-pressure source 82 may then be activated and a reduced pressuredelivered to the shaped dressing bolster 32.

As the pressure is reduced at the shaped dressing bolster 32, the shapeddressing bolster 32 compresses and laterally contracts and forms asemi-rigid substrate, or a less-pliable substrate. The reduced pressureis transmitted through the shaped dressing bolster 32 so that thereduced pressure is applied to the patient's epidermis 14 at the pointof the incision 12. At least at the early stages of the healing processand with certain types of wounds, the reduced pressure may betransmitted through the incision 12 and into the subcutaneous tissue 20and the reduction of pressure may directly help close defects, such asthe subcutaneous void 22, and generally provide stability to the area.The reduced pressure delivered to the shaped dressing bolster 32 alsodevelops the compressive force 24 that again may provide stability,therapy, and may also close or help close the subcutaneous void 22. Thecompressive force 24 is preferably more than just at the epidermis 14.For example, the compressive force 24 can apply a force at the level ofthe subcutaneous tissue 20 or other subdermal anatomy.

As the over-drape 62 and shaped dressing bolster 32 laterally contractunder the influence of the reduced pressure, and as the compressiveforce acts of the epidermis 14, the net closing force 26 develops thatmay help hold the incision 12 closed and may generally provideadditional stability to the area. The effective tensile strength of theincision 12 may be increased. The closing force 26 may rely in part onfriction between the shaped dressing bolster 32 and the epidermis 14 tocommunicate the closing force to the epidermis 14 and may involve forcetransmission from the drape extension 64 to the epidermis 14 by way ofthe adhesive 70 or through friction if tape (172 in FIG. 2) is used. Atthe same time, the reduced pressure delivered to and through shapeddressing bolster 32 helps to remove any exudates or other fluids fromthe incision 12. In one aspect, the reduced-pressure system 10 inhibitsthe formation of wrinkles in the epidermis 14. The system 10 can deliveran even amount of force to the epidermis 14 holding the epidermis 14 ina smooth, or non-wrinkled, configuration for healing.

The reduced-pressure system 10 may avoid skin irritation, such asblistering of the patient's epidermis 14, which may be due to secondaryshear, secondary strain or other effects. To this end, the extremity 33of the shaped dressing bolster 32 may be shaped to provide an evendistribution of radial, compressive forces. The extremity 33 is theouter, shaped portion of the shaped dressing bolster 32 and theperipheral edge is generally the most outboard portion of the shapeddressing bolster 32 or the most outboard portion that interfaces withpatient's skin. The extremity 33 may take a number of different shapesto help evenly distribute the compressive forces or otherwise avoidstress risers. The possible shapes for the extremity 33 include thefollowing: a chamfered (or angled, beveled, or tapered) surface as shownin FIG. 1, an arcuate shape as shown in FIG. 2, or other shape thatdistributes the forces. In contrast, when a bolster with a square-edgeis used, a “tent area” may form when an over-drape is applied over thebolster and onto the patient's epidermis. The “tent area” may contributeto skin irritation unless other steps are taken. The shaped dressingbolster 32 avoids the “tent area.” The shaped edge, or extremity, of thedressing bolster allows a compressive force to be developed without abig “edge effect”; that is, without causing shear or stress to rise to alevel that causes skin irritation, such as erythema or blistering. Theshaped portion of the shaped dressing bolster 32 gradually distributesthe force to avoid irritation. This way of carefully applying the forcesto the skin to avoid irritation is generally referred to as “evenlydistributing” the compressive force, but is not strictly used in aliteral sense. As another precaution against skin irritation, an innerlayer may be added between the shaped dressing bolster 32 and thepatient's epidermis 14 (see, e.g., 857 in FIG. 11) or placed in otherlocations as explained in connection with other illustrative embodimentsfurther below.

It may be desirable to apply the reduced-pressure system 10 in theoperating room and allow the reduced-pressure system 10 to remain on thepatient until adequate healing has taken place. In this regard, it maybe desirable to form the over-drape 62, shaped dressing bolster 32, andany other layers from see-through materials to allow the healthcareprovider to gain visual cues about the healing of the incision 12 anddamaged subcutaneous tissue 20 without having to remove the dressingassembly 30.

Referring now to FIG. 2, another illustrative embodiment of a system 110for treating damaged, or undermined or abnormal, subcutaneous tissue ina patient is presented. The system 110 is analogous in most respects tothe reduced-pressure system 10 and a correlation of parts is generallyindicated in this embodiment by indexing the numerals by 100 and may notbe further referenced. In this particular illustrative embodiment, thesystem 110 is placed over intact epidermis tissue 115, i.e., there is noincision in this instance. There is, however, damaged subcutaneoustissue 120 including a subcutaneous void 122. The system 110 helps withdamaged subcutaneous tissue 120 whether or not there is an incision.

While the shaped dressing bolster 32 of FIG. 1 was shown with atrapezoidal cross-section, the shaped dressing bolster 132 of FIG. 2 hasa cross-section that is formed with a portion having radiused edges, orhaving an arcuate cross-section. The arcuate cross-section of the shapeddressing bolster 132 is an oval or elliptical shape. The shaped dressingbolster 132 may be shaped with a double-beveled cross-section or othershape. As before, the shape of the shaped dressing bolster 132 is tofacilitate “evenly distributing” the radial, compressive force to anextent that skin irritation is avoided during use of the system 110. Anextremity 133 of the shaped dressing bolster 132 is shown having anelliptical cross section. In the illustrative embodiment of FIG. 2, asealing apparatus 169 provides a fluid seal between over-drape 162 andepidermis 114 of the patient, and, in this instance, is a sealing tape172.

The developed forces will now be further described. Ambient pressureprovides a vertical force 131 on a first surface 161 of the over-drape162 and contraction of the shaped dressing bolster 132 develops acompressive force 124 to provide a force that is directed toward theepidermis 114 and that reaches to the subcutaneous levels, i.e., tosubcutaneous tissue 1 18. At the same time, a lateral force, or closingforce, can be developed. The closing force is transferred to theepidermis through the shaped dressing bolster 132. A force 127 is aninward contraction force caused by the shaped dressing bolster 132contracting and compressing. As the shaped dressing bolster 132contracts and compresses, the closing force is transferred to theepidermis 114 through the shaped dressing bolster 132. At the same time,for this illustrative embodiment, as the reduced pressure is applied,the over-drape 162 is drawn into the area proximate the extremity 133 assuggested by arrow 128. Because a drape extension 164 is secured to theepidermis 114, the horizontal component of force 128 would pull theepidermis inward as is suggested by the inward closing force 129.

Referring now primarily to FIG. 3, a system 210 for treating tissue,such as damaged subcutaneous tissue 220, is shown on a curved body part200 such as a patient's torso. A dressing assembly 230 includes a shapeddressing bolster 232. A sealing subsystem 260 includes an over-drape 262and an attachment device 270. A reduced-pressure source (not shown)provides reduced pressure to a reduced-pressure delivery conduit 290,which delivers the reduced pressure to a reduced-pressure interface 292,which in turn delivers the reduced pressure to the shaped dressingbolster 232. As the shaped dressing bolster 232 is compressed under theinfluence of a reduced pressure, a net radial, compressive force 224 isdeveloped that is delivered to the subcutaneous tissue 220. Theover-drape 262 forms a “tent” area around a void 235. Under reducedpressure, the over-drape 262 is pulled into the void 235 and a force isthereby applied that develops an inward contracting force 226.Alternatively, an extremity of the shaped dressing bolster 232 may beshaped to avoid the tent area or the over-drape may be attached to theextremity of the shaped dressing bolster 232.

In the embodiment of FIG. 3, the curvature of the shaped dressingbolster 232 also helps develop the compressive force. A first surface234 of shaped dressing bolster 232 has a greater surface area than asurface area of a second, inward-facing surface 236 of the shapeddressing bolster 232, and under reduced pressure this difference insurface area also facilitates the development of the net compressiveforce 224.

Referring now primarily to FIG. 4, an illustrative system 310 ispresented. The system 310 is generally analogous in most respects tothat of the system 210 of FIG. 3 and analogous parts are indicated byindexing the reference numerals of FIG. 3 by 100 and may not be furthermentioned. The system 310 shows a circumferential dressing assembly 330,which in this illustrative embodiment completely extends around acircumference of a torso. Circumferential forces are developed duringthe application of reduced pressure and combine in the system 310 todevelop the net radial, compressive force 324. The compressive force 324can be relatively higher than a flat or partial-torso applicationbecause there is no off-loading of force to the drape and to theepidermis.

Referring now primarily to FIGS. 5 and 6, another illustrativeembodiment of a dressing assembly 430 is presented. The dressingassembly 430 has a shaped dressing bolster 432 with a first surface 434and a second, inward-facing (skin-facing or patient-facing) surface 436.In this illustrative embodiment, the shaped dressing bolster 432 hasbeen formed with an oblique extremity 433, and in particular with atrapezoidal cross-section in two orthogonal planes, such as orthogonalplanes 440 and 442. A cross-section along one such plane of the dressingassembly 430 is shown in FIG. 6. The peripheral edge 438 of the shapeddressing bolster 432 is formed with an angle alpha (α) between avertical (for the orientation shown), or normal, reference line 444 anda surface extension line (in cross-section) 446. The angle alpha (α)would typically be between 3 degrees and 95 degrees, and more typicallybetween 20 and 65 degrees, and more typically still about 45 degrees.

An over-drape 462 is placed over the shaped dressing bolster 432. Theover-drape 462 extends beyond a peripheral edge 438 to form drapeextensions 464, each having a first side 466 and a second, inward-facingsurface 468. The over-drape 462 may be coupled using any of a number ofdevices or techniques, such as with adhesives and bonding as previouslymentioned. In this illustrative embodiment, the over-drape 462 iscoupled by a bond 450 to an exterior 439 of the peripheral edge 438. Theover-drape 462 may also be coupled to an exterior surface 435 of thefirst surface 434 of the shaped dressing bolster 432. In thisillustrative embodiment, the over-drape 462 may be coupled, at leastpartially, to substantially all of the exterior surfaces of the shapeddressing bolster 432, except the surface facing the patient. When theover-drape 462 is coupled to substantially all the exterior surfaces ofthe shaped dressing bolster 432 except the inward-facing surface, theperipheral edge 438 may be shaped to have right angles and yet avoidskin irritation because no “tent area” can form. Otherwise, the edge 438is shaped to be other than at a right angle. Alternatively, a layer maybe added to help minimize skin irritation.

As shown in FIG. 5, a reduced-pressure delivery conduit 490, which ispart of a reduced-pressure subsystem, can be used to supply reducedpressure to a reduced-pressure interface 492 that delivers reducedpressure into the shaped dressing bolster 432. The reduced-pressureinterface 492 may be a port 494 or a direct application into the bolster432 or other device.

Referring now primarily to FIG. 7, another illustrative embodiment of adressing assembly 530 is presented. The dressing assembly 530 has ashaped dressing bolster 532 formed to have a rectangular cross-section.In this instance, an over-drape 562 is coupled, such as by bonding withbond 550, to an exterior surface 539 of a peripheral edge 538 and to afirst surface 534 of the shaped dressing bolster 532. The bond 550 mayfacilitate more even application of the radial, compressive force to thepatient even though the shaped dressing bolster 532 is shaped with rightangles. While the coupling is shown as complete along the exterior 539of the peripheral edge 538 and on an exterior surface 535 of the firstsurface 534, the coupled portion may be partial or accomplished withtacking.

Referring now primarily to FIG. 8, another illustrative embodiment of adressing assembly 630 is presented. The dressing assembly 630 has ashaped dressing bolster 632 that is formed to have an arcuatecross-section, which, in this instance, is an elliptical or ovalcross-section. As such, the peripheral edge 638 has a radius or curvedshape. The over-drape 662 may be coupled by bonding 650 on an exteriorsurface 639 of the peripheral edge 638 and on an exterior surface 635 ofa first surface 634 of the shaped dressing bolster 632. The ellipticalcross-section may exist in two different orthogonal planes.

Referring now primarily to FIG. 9, an illustrative embodiment of amedical bolster material 635 is presented with reference to a first axis674, a second axis 676, and a third axis 678. The medical bolstermaterial 635 may be used for any of the shaped dressing bolsterspreviously mentioned. While in many applications, the medical bolstermaterial 635 may be isotropic, in other applications it may be desirableto have an anisotropic material like the medical bolster material 635.

Anisotrophy is generally the property of being directionally dependent,as opposed to isotropy, which means homogeneity in all directions. Forexample, if it is desirable to produce a stronger force that opposesgravity that is applied to an exterior of a patient, anisotropicmaterial may be used so that when net circumferential force is developedalong the first axis 674, a greater movement is developed along thevertical axis-in this instance the third axis 678 for the orientationshown. In still other instances, it may be desirable to also have adifferent performance in the direction of the second axis 676. Theanisotropic material may be formed by adding filaments in a firstdirection. The anisotropic material may also be formed by felting (heatcompression) of the material to make lines of differing densities. Theanisotropic material may also be formed by using an adhesive thatimparts strength in a given direction.

Referring now primarily to FIG. 10, a portion of an illustrativeembodiment of a system 710 for treating tissue, such as damagedsubcutaneous tissue, is shown. The system 710 includes a shaped dressingbolster 735, a sealing subsystem 760, and a reduced-pressure subsystem780 for which only a portion is shown. The shaped dressing bolster 735may be part of a dressing assembly 730 that includes a breathable drylayer 741 having a first surface 743 and a second, inward-facing surface745. The dressing assembly 730 also may include a non-breathable layer747, which has a first surface 749 and a second, inward-facing surface751. The sealing subsystem 760 includes an over-drape 762 similar to thepreviously discussed embodiments and an attachment device 770.

A number of materials are possible for the various layers 741, 732, 747.The breathable dry layer 741 may be formed, for example, from ahydrophilic non-woven material that allows fluids to flow into theshaped dressing bolster 735. The breathable dry layer 741 may be acomfort layer that helps avoid skin irritation or otherwise enhancescomfort. The shaped dressing bolster 735 may be formed from a relativelythin absorbent structure or material that can store relatively largequantities of fluid. For example, the shaped dressing bolster 735 may beformed from a superabsorbent polymer (SAP) of the type often referred toas “hydrogels,” “super-absorbents,” or “hydrocolloids.” The shapeddressing bolster 735 may also be formed from any of the previouslymentioned manifold materials. The non-breathable layer 747 may be formedfrom a number of different materials, e.g., a polyethylene film thatwill keep fluids from leaking out. Additional substrates may be added.The various layers 741, 732, 747 may be sealed or combined withadhesives such as a hot melt adhesive or heat bonded or coupled usingany technique or device.

In operation, as fluid is added to the shaped dressing bolster 735, theshaped dressing bolster 735 becomes more rigid (less pliable), and underreduced pressure, this results in an increased radial, compressiveforce, such as radial force 24 in FIG. 1. The fluid may come in the formof exudates or other fluids from the wound or may be a supplied fluidsuch as a saline that is intentionally added through a second port,second lumen, or by injecting through the dressing assembly in aninjection port. In this sense, the shaped dressing bolster 735 may beregarded as a liquid-controlled bolster since additional liquid can beadded to make the shaped dressing bolster 735 more rigid (less pliable)and that results in a greater force.

Still referring to FIG. 10, an alternative illustrative embodiment ofthe dressing assembly 730 is presented by describing other possibleelements. In this illustrative embodiment, the bolster includes twomembers: a first bolster layer 741, which is formed from a hydrophilicfoam, and a second bolster layer 732, which is formed from a hydrophobicfoam. The over-drape 762 is then placed over a first surface (topsurface for orientation shown) of the second bolster layer 732. Otherlayers of various materials may be added as well.

Referring now primarily to FIG. 11, an illustrative embodiment of adressing assembly 830 for use with a system for treating tissue, e.g.,damaged subcutaneous tissue, is presented. The dressing assembly 830includes a shaped dressing bolster 832 and an over-drape 862, which aregenerally analogous to those presented in other embodiments herein. Asealing subsystem 830 includes the over-drape 862 that extends beyondthe shaped dressing bolster 832 to form drape extensions 864, which havea first surface 866 and a second, inward-facing side, 868. A sealingapparatus 869 may be used to provide a seal between the drape extension864 and the patient's epidermis 814. In this illustrative embodiment,the sealing apparatus 869 is an adhesive 867, which is placed on thesurface facing the patient. The adhesive 867 may initially be coveredwith a covering, or releasable backing, that may be peeled off beforethe dressing assembly 830 is applied to a patient's epidermis 814. Thedressing assembly 830 shows the addition of an inner layer 853 having afirst surface 855 and a second, inward-facing surface 857. The innerlayer 853 is formed with a treatment-area aperture 859.

The inner layer 853 may help reduce or eliminate skin irritation thatmay result between the shaped dressing bolster 832 and the patient'sepidermis 814. The inner layer 853 may be an acrylic drape material suchas an Avery brand Acrylic drape, a Scapa brand Silicone drape, oranother suitable material. The inner layer 853 is placed around aperimeter of the second surface 836 of the shaped dressing bolster 832where the shaped dressing bolster 832 would otherwise interface's withthe patient's skin. The inner layer 853 and the over-drape 862encapsulate the shaped dressing bolster 832, except for the treatmentarea aperture 859. An adhesive may be applied on the second surface 857of the inner layer 853 to promote a splinting effect over an area wherethe shaped dressing bolster's 832 interaction with the epidermis endsand the over-drape's 862 interaction with the epidermis begins. Thisarrangement may help to prevent blistering due to high concentrations ofshear stress and strain when the reduced pressure is applied because theadhesive is believed to help deter the epidermis from rolling or ballingup and forming a pressure point or pressure rise.

Referring now primarily to FIG. 12, an illustrative embodiment of adressing assembly 930 is shown in an exploded view. The dressingassembly 930 has a shaped dressing bolster 932, an inner layer 953, andan over-drape 962. The inner layer 953 has a first surface 955, asecond, inward-facing surface 957, and is formed with a treatment-areaaperture 959. The shaped dressing bolster 932 is an example of a shapeddressing bolster 932 having an oblique surface (peripheral edge 938 isformed with angle to a vertical axis) and thus, in this instance, formsa trapezoidal cross-section in at least two orthogonal planes. Theshaped dressing bolster 932 has a first surface 934 and a second,inward-facing surface 936. The over-drape 962 has a first surface 966and a second, inward-facing surface 968.

The inner layer 953 may be used in a number of ways to address thepotential for skin irritation. In one illustrative embodiment, thesecond surface 936 of the shaped dressing bolster 932 is coupled to thefirst surface 955 of the inner layer 953. In another illustrativeembodiment, no adhesive or other attachment device is used between theshaped dressing bolster 932 and the inner layer 953 so as to allowrelative movement between the shaped dressing bolster 932 and the innerlayer 953. Similarly, the second surface 968 of the over-drape 962 maybe coupled to the first surface 934 of the shaped dressing bolster 932.In an alternative embodiment, there may be no attachment device betweensurfaces 934 and 968.

Still another illustrative embodiment involves coupling all the exteriorsurfaces of the shaped dressing bolster 932 to the over-drape 962,except the second, inward-facing surface 936 of the shaped dressingbolster 932. An adhesive or other attachment device may be used tocouple the first surface 955 of the inner layer 953 to the secondsurface 936 of the shaped dressing bolster 932. No adhesive orattachment device is administered on the second surface 957 and so skinirritation may be reduced because the relatively low friction surface ofthe inner layer 953 is allowed to slide relative to the skin.Alternatively, an adhesive or other attachment device may be applied onthe second surface 957 of the inner layer 953 to hold the inner layer953 to the epidermis, but not between the shaped dressing bolster 932and the inner layer 953 so as to allow lower-friction movement betweenthe shaped dressing bolster 932 and the inner layer 953.

In yet another alternative of this illustrative embodiment, an adhesiveor other adhesive device may be applied between the second surface 936of the shaped dressing bolster 932 and the first surface 955 of theinner layer 953 and between the second surface 957 of the inner 953 andthe patient's epidermis. With this alternative, a splinting effect isachieved in the area where the interaction of the shaped dressingbolster 932 with the epidermis ends and the inner layer's 953interaction with the epidermis begins. This arrangement helps to preventblistering due to high concentrations of shear stress and strain placedin that location when reduced pressure is applied. The adhesive orattachment device is believed to prevent the epidermis from rolling orballing up and forming a pressure point or pressure rise. The innerlayer 953 configurations may be used on any of the illustrativeembodiments presented as well as others.

Referring now primarily to FIGS. 13 and 14, an illustrative embodimentof a dressing assembly 1030 is presented. The dressing assembly 1030 hasa shaped dressing bolster 1032 with a first surface 1034 and a secondsurface 1036. An extremity 1033 of the shaped dressing bolster 1032 isangled in this illustrative embodiment. An inner layer 1053 is providedhaving a first surface 1055 and a second, inward-facing surface 1057,but in this instance, the second surface 1057 is placed adjacent to theperipheral edge 1038 of the shaped dressing bolster 1032. The innerlayer 1053 is formed with a central aperture 1059. The inner layer 1053and a portion of shaped dressing bolster 1032 are covered with anover-drape 1062. Adhesive or another attachment device may be usedbetween the first surface 1055 of the inner layer 1053 and secondsurface 1063 of the over-drape 1061 or between the second surface 1057of the inner drape 1053 and the first surface 1034 of the shapeddressing bolster 1032.

Referring now primarily to FIGS. 15-16, a portion of a system 1110 fortreating a linear wound, area wound, other wound, or graft is presented.The portion of the system 1110 is presented in FIG. 15 in apre-deployment state.

The system 1110 includes a dressing assembly 1130, which includes ashaped dressing bolster 1132. The shaped dressing bolster 1132 has afirst side 1134 and a second, inward-facing side 1136. The shapeddressing bolster 1132 may be formed from any medical bolster material aspreviously discussed with other embodiments. A comfort layer 1170, whichhas a first side 1172 and a second, inward-facing side 1174, may becoupled, e.g., by a heat bond 1176 or any other technique, to the secondside 1136 of the shaped dressing bolster 1132.

The comfort layer 1170 may be any material that helps prevent skinirritation and discomfort while allowing fluid transmission through thecomfort layer 1170. As one non-limiting example, a woven, elasticmaterial may be used or a polyester knit textile substrate. As anothernon-limiting example, an InterDry textile material from MillikenChemical of Spartanburg, S.C., may be used. The comfort layer 1170 mayinclude anti-microbial substances, such as silver. The comfort layer maybe made like the breathable, dry layer 741 of FIG. 10.

In one embodiment, the shaped dressing bolster 1132 may include aplurality of flexibility notches 1178. The flexibility notches 1178 maybe lateral notches, or lateral cuts, in the shaped dressing bolster 1132as shown and, in addition or alternatively, may be one or morelongitudinal notches, or longitudinal cuts, or other cuts. The cuts maybe made using a saw (or notched blade), a hot knife, or other device.The flexibility notches 1178 enhance flexibility of the shaped dressingbolster 1132. The enhanced flexibility may be particularly useful whenthe dressing assembly 1130 is applied over a patient's joint or otherarea of movement. For example, if the shaped dressing bolster 1132 isused on a knee, the shaped dressing bolster 1132 may need to flex orextend as much as 100% or more, and the flexibility notches 1178 orridges help provide the desired flexibility. In addition, a plurality offolds 1173 may be added to facilitate movement as described furtherbelow.

In one illustrative embodiment, the shaped dressing bolster 1132 ismanufactured as follows. A block of Granufoam® material, e.g., 1.21meter×1.8 meter×0.5 meter block, is cut to have a 19 mm height, and asaw is used to form lateral grooves, or lateral flexibility notches1178. Then, a dry layer, which may be the comfort layer 1170, islaminated onto the second, or bottom, surface. Then, the foam block iscut using a die cut to form the individual shaped dressing bolsters1132.

A sealing subsystem 1160 provides a fluid seal over the dressingassembly 1130 and at least a portion of the patient's epidermis. Thesealing subsystem 1160 includes an over-drape 1162, which may be formedwith a first over-drape portion 1163 and a second over-drape portion1165. The first over-drape portion 1163 extends over the first side 1134of the shaped dressing bolster 1132 and extends further to form a drapeflange, or drape extension 1164, which has a first side 1166 and asecond, inward-facing side (not explicitly shown). An aperture 1181 isformed on a portion of the first over-drape 1163. The aperture 1181 isfor allowing fluid communication with a reduced-pressure interface(e.g., reduced-pressure interface 92 in FIG. 1)

The second, inward-facing side of the drape extension 1164 is placed ona first side 1167 of the second over-drape portion 1165 and coupled,such as by an adhesive, bond 1169, other coupling technique or device,such as those previously mentioned. The first drape portion 1163 mayinclude the plurality of folds 1173, or bellows. The folds 1173 allowthe first drape portion 1163 to expand if needed. For example, if thedressing assembly 1130 is used on a joint, when the joint is flexed, thedrape portion 1163 is extended using the folds 1173. Additional drapematerial may be released from the folds 1173 to facilitate movement. Thesecond, inward-facing side of the second drape portion 1165 may have anadhesive on a portion and may have a treatment area aperture (see byanalogy treatment area aperture 1271 in FIG. 17). The folds 1173 mayalso be formed as ridges that in cross section would appear asaccordion-like ridges that flatten out when stretched and therebyprovide additional material.

One or more release members 1182 may be releasably coupled to the firstside 1167 of the second drape portion 1165. Four release members 1182are shown in the illustrative embodiment of FIG. 15. The release members1182 provide stiffness and help during deployment of the dressingassembly 1130. The release members 1182 are typically either castingpaper or a film held on the first side 1167 of the second drape portion1165.

Referring now primarily to FIG. 17, an exploded perspective view of aportion of a system 1210 for treating tissue, e.g., subcutaneous tissue,a linear wound, area wound, other wound, or graft is presented. Theportion of the system 1210 presented in FIG. 17 is shown in apre-deployment state and in an exploded view. The system 1210 isanalogous in most respects to the system 1110 of FIGS. 15-16, and toindicate corresponding parts, the reference numerals have been indexedby 100 and may not be further mentioned. The system 1210 includes adressing assembly 1230, which includes a shaped dressing bolster 1232.The shaped dressing bolster 1232 is the same as shaped dressing bolster1132, but the flexibility notches 1278 are both lateral andlongitudinal.

The first side 1234 of the shaped dressing bolster 1232 is covered by anover-drape 1262, which may include a first drape portion 1263 and asecond drape portion 1265. The first drape portion 1263 includes folds1273 and an aperture 1281. The second drape portion 1265 is formed witha treatment area aperture 1271 that provides an opening for at least aportion of the shaped dressing bolster 1232 (or a comfort layer) to bedirectly against a patient's epidermis or treatment site. The seconddrape portion 1265 has first side 1267 and has an adhesive 1283 appliedon a portion of the first side 1267. The adhesive 1283 is used primarilyduring manufacture to hold the shaped dressing bolster 1232 against thesecond drape portion 1265 during assembly and also used to help hold theshaped dressing bolster 1232 during use. Before applying the shapeddressing bolster 1232 against the adhesive 1283, the adhesive 1283 iscovered by a center releaseable member 1284. Outboard of the adhesive1283 on the first side 1267 are releaseable members 1282 that providesstiffness to the over-drape 1262 during deployment.

The second, inward-facing side (not explicitly shown but opposite sideof the first side 1267) of the second drape portion 1265 may be coveredwith an adhesive. In the pre-deployment state, this adhesive is coveredby a bottom release member 1286 and side release members 1287.

Once assembled, the portion of the system 1210 resembles the portion ofthe system 1120 of FIG. 15. The use and design may vary, but in oneillustrative embodiment, the portion of the system 1210 may deployed aswill be described. The bottom release liner 1286 is removed and theexposed adhesive on the second, inward-facing side of the second drapeportion 1265 is placed against a portion of the patient's epidermisbeginning at one end and may be placed over a linear wound. Aftersmoothly applying the second drape portion 1265, the side releasemembers 1287 are removed. The release members 1282 on the first side1267 of the over-drape 1262 are removed. A reduced-pressure interface iscoupled to the aperture 1282 in the first over-drape portion 1263. Thecenter release member 1284 was already removed during manufacture.

With respect to manufacturing the systems and components describedabove, the components and their assembly have been presented. Inapplying and coupling an over-drape to the first surface of a shapeddressing bolster, it may be desirable to utilize a press to remove anywrinkles that may otherwise result or remain. The medical bolstermaterial of the shaped dressing assembly may be cut using a die cut orby hand with a router.

According to another illustrative embodiment, a reduced-pressure systemfor treating a tissue site includes a directed-force member, which has anon-orthogonal edge, e.g., a curved edge, a slanted or angled edged, oran edge with a portion of a drape adhered to the edge, for evenlydistributing a force when placed under reduced-pressure. Thedirected-force member may be formed as a foam member with a plurality ofchannels for transmitting a fluid. The reduced-pressure system furtherincludes the drape for providing a fluid seal over at least a portion ofthe directed-force member and a patient's epidermis. The system also mayhave a reduced-pressure conduit for fluidly coupling a reduced-pressuresource and the directed-force member. In one illustrative embodiment,the directed-force member is a foam member with a tapered edge. Whenreduced-pressure is delivered by the reduced-pressure source to aninterior portion through the drape, the reduced pressure causes thedirected-force member to exert a force. The force may include a verticalforce against a patient's epidermis or other tissue that may penetrateto more than 1 millimeter, more than 2 millimeters, more than 3millimeters, more than 4 millimeters, more than 5 millimeters, more than7 millimeters, and even deeper. The vertical force may help approximatedead space and voids. The force may be or include a closing force.

According to another illustrative embodiment, a reduced-pressure,force-generating dressing assembly includes a directed-force member thathas an oblique edge for evenly distributing a force when placed underreduced-pressure. The directed-force member has a top side and a bottomside. The directed-force member is formed from a medical bolstermaterial, which has a plurality of channels. The flow channels may beinterconnected, e.g., a foam. The dressing assembly may further includea drape for providing a fluid seal over at least a portion of thedirected-force member and a patient's epidermis. The directed-forcemember may have an angled extremity. Alternatively, the directed-forcemember may have an arcuate extremity. The dressing assembly may alsohave a comfort layer coupled to the bottom side of the directed-forcemember. The comfort layer may be a breathable dry layer coupled to thebottom side of the directed-force member or any other material thathelps to avoid maceration of the skin or skin irritation of any kind.

According to another illustrative embodiment, a method of treating adamaged subcutaneous tissue on a patient includes positioning a shapeddressing bolster over the damaged subcutaneous tissue. The shapeddressing bolster has an oblique extremity and is formed from a medicalbolster material. The method further includes deploying an over-drapeover the shaped dressing bolster and a portion of the patient'sepidermis to provide a fluid seal and providing a reduced-pressuresource. The method also includes coupling a reduced-pressure interfaceto the drape and fluidly coupling a reduced-pressure delivery conduit tothe reduced-pressure source and to the reduced-pressure interface. Themethod also involves activating the reduced-pressure source to providereduced pressure to the shaped dressing bolster to develop a compressiveforce and a closing force. The compressive force may be realized at asubcutaneous tissue or other subdermal anatomy.

Although the present invention and its advantages have been disclosed inthe context of certain illustrative, non-limiting embodiments, it shouldbe understood that various changes, substitutions, permutations, andalterations can be made without departing from the scope of theinvention as defined by the appended claims. It will be appreciated thatany feature that is described in a connection to any one embodiment mayalso be applicable to any other embodiment.

1. A dressing assembly for use with a reduced pressure treatment system,the dressing assembly comprising: a shaped dressing bolster having afirst surface, a second, inward-facing surface; an oblique extremityformed a portion of the shaped dressing bolster; wherein the shapeddressing bolster is formed from a medical bolster material, the shapeddressing bolster for placing on the patient's epidermis; wherein themedical bolster material has a density greater than 20 kg/m³; andwherein the shaped dressing bolster has the characteristic of evenlydistributing a directed force when under a reduced pressure. 2.(canceled)
 3. The dressing assembly of claim 1 wherein the obliquesurface of the extremity makes an angle alpha (α) with a normalreference and wherein the angle alpha (α) is greater than ten degrees(α>10 degrees).
 4. The dressing assembly of claim 1 wherein the obliquesurface of the extremity makes an angle alpha (α) with a normalreference and wherein the angle alpha (α) is in a range between 10degrees and 70 degrees (70°>α>10°).
 5. (canceled)
 6. The dressingassembly of claim 1 further comprising an over-drape disposed over thefirst surface of the shaped dressing bolster.
 7. The dressing assemblyof claim 1 further comprising: an over-drape disposed over the firstsurface of the shaped dressing bolster; and a drape sealing apparatuscoupled to the over-drape for sealing the over-drape to a patient'sepidermis. 8.-9. (canceled)
 10. The dressing assembly of claim 1 whereinthe shaped dressing bolster further comprises a plurality of flexibilitynotches formed on the first surface of the dressing bolster. 11.(canceled)
 12. The dressing assembly of claim 1 wherein the shapedextremity comprises a member with a trapezoidal cross-section in twoorthogonal planes.
 13. The dressing assembly of claim 1 wherein theshaped extremity comprises a member with an arcuate cross-section in twoorthogonal planes.
 14. The dressing assembly of claim 1 wherein theshaped extremity comprises a member with an elliptical cross-section intwo orthogonal planes. 15.-18. (canceled)
 19. The dressing assembly ofclaim 1 further comprising a comfort layer coupled to the second,inward-facing surface of the shaped dressing bolster
 20. The dressingassembly of claim 1 further comprising an over-drape disposed over thefirst surface of the shaped dressing bolster and wherein at least aportion of the first surface of the shaped dressing bolster is coupledto a portion of the over-drape. 21.-22. (canceled)
 23. The dressingassembly of claim 1 wherein the shaped dressing bolster comprises areticulated foam having a density greater than 25.6 kg/m³.
 24. Thedressing assembly of claim 1 wherein the shaped dressing bolstercomprises a reticulated foam having a density greater than 32.0 kg/m³.25.-26. (canceled)
 27. The dressing assembly of claim 1 furthercomprising: an inner layer having a first surface and a second,inward-facing surface and wherein the first surface of the inner layeris coupled, at least in part, to a portion of the second surface of theshaped dressing bolster.
 28. (canceled)
 29. The dressing assembly ofclaim 1 further comprising: an over-drape; a plurality of flexibilitynotches formed on the first surface of the dressing bolster; an innerlayer having a first surface and a second, inward-facing surface andwherein the first surface of the inner layer is coupled, at least inpart, to a portion of the second surface of the shaped dressing bolster;and wherein the oblique surface of the extremity makes an angle alpha(α) with a normal reference and wherein the angle alpha (α) is in arange between 25 degrees and 65 degrees (65°>α>25°).
 30. A dressingassembly for use with a reduced pressure treatment system, the dressingassembly comprising: a shaped dressing bolster having an obliqueextremity and having a first surface and a second, inward-facingsurface; an over-drape disposed over the first surface of the shapeddressing bolster and coupled to a least a portion of the first surfaceof the shaped dressing bolster and wherein the over-drape extends beyondthe shaped dressing bolster to form a drape extension, the drapeextension having a first side and a second, inward-facing side; and anadhesive perimeter strip coupled to the second side of the drapeextension and operable to provide a seal between a patient and theover-drape. 31.-32. (canceled)
 33. The dressing assembly of claim 30wherein the shaped dressing bolster comprises a medical bolster materialshaped to have a trapezoidal cross-section in two orthogonal planes. 34.The dressing assembly of claim 30 wherein the shaped dressing bolstercomprises a medical bolster material shaped to have an extremity with across-section forming an arcuate portion in two orthogonal planes. 35.The dressing assembly of claim 30 wherein the shaped dressing bolstercomprises a medical bolster material shaped to have an ellipticalcross-section in two orthogonal planes. 36.-42. (canceled)
 43. Areduced-pressure, force-generating dressing assembly, the dressingassembly comprising: a directed-force member having an oblique edge forevenly distributing a directed force when placed under reduced-pressure,the directed-force member having a top side and a bottom side; whereinthe directed-force member is formed from a medical bolster materialhaving a plurality of channels; and a drape for providing a fluid sealover at least a portion of the directed-force member and a patient'sepidermis.
 44. The dressing assembly of claim 43 wherein the pluralitythe plurality of channels are interconnected.
 45. The dressing assemblyof claim 43 wherein the directed-force member has an angled extremity.46. The dressing assembly of claim 43 wherein the directed-force memberhas an arcuate extremity.
 47. The dressing assembly of claim 43 furthercomprising a comfort layer coupled to the bottom side of thedirected-force member.
 48. The dressing assembly of claim 43 furthercomprising a breathable dry layer coupled to the bottom side of thedirected-force member.
 49. A method for treating damaged subcutaneoustissue on a patient, the method comprising: positioning a dressingassembly over the damaged subcutaneous tissue, wherein the dressingassembly has a shaped dressing bolster having an oblique extremity andthat is formed from a medical bolster material; deploying an over-drapeover the dressing assembly and a portion of the patient's epidermis toprovide a fluid seal; providing a reduced-pressure source; coupling areduced-pressure interface to the over-drape; fluidly coupling areduced-pressure delivery conduit to the reduced-pressure source and tothe reduced-pressure interface; activating the reduced-pressure sourceto provide reduced pressure to the dressing assembly to develop acompressive force and a closing force.
 50. The method of claim 49wherein the shaped dressing bolster comprises a reticulated foam havinga density greater than 25.6 kg/m³.
 51. The method of claim 49 whereinthe shaped dressing bolster comprises a reticulated foam having adensity greater than 32.0 kg/m³.
 52. (canceled)